Abstract Osteopenia is a highly common skeletal condition with accelerated loss of bone mass that leads to osteoporosis. Characterized by below normal bone mineral density (BMD), osteopenia affects 43 million Americans. If BMD loss is not mitigated, patients become osteoporotic and are at increased risk of bone fractures, particularly of the hip and spine. Such fractures decrease independent living, shorten life and increase morbidity. Clinical guidelines for treating osteopenia include both dietary modifications and high impact exercise. While diet and exercise are highly effective in maintaining BMD, compliance is low. The alternative is prescribed bisphosphonates, which effectively inhibit bone resorption. However, serious adverse events with prolonged use limit their use to patients with osteoporotic levels of BMD, when their antifracture benefits considerably outweigh their potential for harm. Our scientific premise is that delivering mechanical stimulation to the hips and spine via a wearable vibration device can serve as a surrogate for exercise and thus, an effective non-drug intervention for osteopenia. Whole body vibration, which is administered by standing on a vibrating platform, has demonstrated significant improvement in BMD in some cases. However, with substantial attenuation of vibration as it passes through the body, a high and unsafe vibration magnitude is required to elicit an improvement in hip and spine BMD in older individuals. TheraNova has developed Mimetix, a novel wearable vibration device designed to provide controlled, safe and therapeutic mechanical stimulation localized to the hip and spine in order to mitigate bone mass loss and fracture risk. In our clinical Phase I studies, we successfully demonstrated that Mimetix provides: (1) Delivery of consistent mechanical stimulation localized to the hips and spine, (2) Effective mitigation of bone resorption (observed via bone turnover markers (BTMs)) using safe magnitudes of vibration and (3) Enhanced potential for patient compliance based on ease-of-use and comfort. The goal of this proposal is to validate the efficacy of Mimetix treatment on improving bone resistance to fracture (bone strength) and BMD. In Specific Aim 1, we will conduct a 6-week study with 20 postmenopausal patients to verify that the Mimetix device can be tuned to apply a consistent acceleration dose to each patient. During both in-clinic and at-home use, accelerations will be monitored via body worn accelerometers to validate personalized device calibration for delivery of consistent levels of vibrational acceleration that are both therapeutic and safe (a) across different patients; (b) over an extended time period; and (c) during at-home daily activities. In Specific Aim 2, we will conduct an 18-month, prospective, single-blinded, at-home study to validate the efficacy of mechanical stimulation via the Mimetix device compared to a sham device in 110 postmenopausal, osteopenic patients. Efficacy will be evaluated based on (a) hip bone strength, (b) hip and spine BMD and (c) BTMs indicative of both bone formation and resorption. Once completed, the results from these studies support regulatory approval and commercialization, allowing Mimetix to meet the large, unmet clinical need for a simple, non-invasive, effective treatment for osteopenia.